Various dyeing processes which use gum have heretofore been developed. In these processes a viscous gum layer is applied to the pile face of a carpet web being carried along a continuous conveyer. The gum acts as a carrier for the dye or as a barrier layer on the pile face of the carpet web. Although the gum layer is generally applied prior to application of dye to the pile face, some processes include a preliminary treatment of the web with dye prior to the application of gum and subsequent and further dye treatment after the application of gum layer. In either case, the final dye application is either applied on top of the viscous gum layer or mixed therewith.
In a particular popular dyeing process known as the TAK dye process which is the subject matter of U.S. Pat. Nos. 3,683,649; 3,731,503 and 3,800,568, jets of dye are dispersed from above into individual dye droplets along the breadth of a continuously traveling textile carpet web. Prior to application of the liquid dye, there is usually applied across the breadth of the carpet web, which is conventionally from 12 to 15 feet in width, a continuous layer of gum in the order of 1/2 to 1/4 inch thick. This gum layer covers the pile face of the carpet web as shown, for example, in the U.S. Pat. No. 4,189,302. In one known process described in U.S. Pat. No. 4,010,709 the dye is caused to form in pools or puddles when applied onto the barrier layer of gum. Because of higher viscosity of the gum layer, dye penetration through the gum layer is delayed until the carpet web is passed through a steamer where the gum becomes less viscous and flows between the yarns to the base of the web, while the dye color is set or fixed in the yarns. Such gum based dyeing processes have achieved wide popularity because of their ability to achieve unusual and varying non-repetative random color patterns despite the increased manufacturing costs resulting from use of such large quantities of gum.
Following the application of the gum and dye and the setting of the dye in the steamer, the carpet web is passed through a rinsing (i.e., washing) stage wherein the carpet web is sprayed with water to wash off excess gum, dyes and other chemicals, the gum and rinse water normally being dumped into a municipal sanitary disposal system. After rinsing, the carpet web is passed through a dryer wherein the carpet web is dried and thence to a collecting box from which it is rolled.
Although the prior art gum based dyeing processes have been most useful in developing unique color patterns, such dyeing processes are subject to a number of disadvantages. In particular, such processes require a large amount of gum which is wasteful and costly. More importantly, the gum which is washed out at the rinsing stage is most likely to be flushed into the local sanitary sewage system, local streams or holding pools from which it may seep into the ground. Such disposal creates a series environmental problems which are only now being given serious attention by local and federal agencies.
Additionally, these prior art processes use a relatively large amount of heated water which in turn requires the use of relatively large amounts of energy, especially at the steaming stage and drying stage of such processes. The energy requirements for these processes, as well and the pollution resulted from chemical disposal cause operational costs to be relatively high.